Is CVE-2026-26308 actively exploited?

No active exploitation of CVE-2026-26308 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-26308 be exploited remotely?

Yes. CVE-2026-26308 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-26308?

CVE-2026-26308 has a CVSS score of 8.2 (HIGH).

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HIGH

CVE-2026-26308

CWE-863Published: March 10, 2026· Updated: Mar 11, 2026

8.2

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:7.7th

Official Description

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, the Envoy RBAC (Role-Based Access Control) filter contains a logic vulnerability in how it validates HTTP headers when multiple values are present for the same header name. Instead of validating each header value individually, Envoy concatenates all values into a single comma-separated string. This behavior allows attackers to bypass RBAC policies—specifically "Deny" rules—by sending duplicate headers, effectively obscuring the malicious value from exact-match mechanisms. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

NVD Source

Technical Analysis

CVE-2026-26308 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 8.2.